[C++] Simplify arrow::ArrayStatistics::ValueType

[kou]

Describe the enhancement requested

We can cover integer values by int64_t and uint64_t and float values by double.
We can remove std::string_view because we don't support out of ArrayStatistics string/binary data.

See also: https://github.com/apache/arrow/pull/43273/files/2c60782ced9b1f75b9089ed36dc2fd326cc96523#r1704278599

Component(s)

C++

[kou]

Issue resolved by pull request 43581
#43581